Re: [PATCH] net/mlx5: fix data access race condition for shared Rx queue

[Raslan Darawsheh <rasland@nvidia.com>]

Hi,

From: Jiawei(Jonny) Wang <jiaweiw@nvidia.com>
Sent: Friday, July 5, 2024 4:05 PM
To: Bing Zhao; Slava Ovsiienko; Dariusz Sosnowski; Ori Kam; Suanming Mou; Matan Azrad; Alexander Kozyrev
Cc: dev@dpdk.org; Raslan Darawsheh; stable@dpdk.org
Subject: [PATCH] net/mlx5: fix data access race condition for shared Rx queue

The rxq_data resources were shared for shared Rx queue with the same
group and queue ID.
The cq_ci:24 of rxq_data was unalignment with other fields in the one
32-bit data, like the dynf_meta and delay_drop.

  32bit:  xxxx xxxI IIII IIII IIII IIII IIII IIIx
                  ^ .... .... .... .... ...^
                  |          cq_ci         |

The issue is that while the control thread updates the dynf_meta:1 or
delay_drop:1 value during port start, another data thread updates the
cq_ci at the same time, it causes the bytes race condition with
different thread, and cq_ci value may be overwritten and updated the
abnormal value into HW CQ DB.

This patch separates the cq_ci from the configuration data spaces, and
adds checking for delay_drop and dynf_meta if shared Rx queue if
started.

Fixes: 02a6195cbe ("net/mlx5: support enhanced CQE compression in Rx burst")
Cc: stable@dpdk.org

Signed-off-by: Jiawei Wang <jiaweiw@nvidia.com>
Acked-by: Bing Zhao <bingz@nvidia.com>
Acked-by: Viacheslav Ovsiienko <viacheslavo@nvidia.com>

Patch applied to next-net-mlx,

Kindest regards,
Raslan Darawsheh